1. Technical Field of the Invention
The present invention relates to a motor vehicle door lock, more particularly to an electric side door lock of a motor vehicle body.
2. Description of the Prior Art
A motor vehicle door lock in the form of an electric lock has long been known as disclosed in DE 195 45 722 A1.
In accordance with the present invention it should be considered that in the terminology a xe2x80x9cmotor vehicle door lockxe2x80x9d is defined particularly as side door locks of motor vehicle bodies, but may also include door locks for rear doors or rear hatches, for sliding doors and hoods, to the extent they are provided with an electric motorized opening aid. The expression motor vehicle door lock or the expression electric lock is used below representatively for the different types of door locks.
Further, in accordance with the present invention the key collar is defined as a wedge-shaped clamp in a narrow sense, but may also include locking clips, locking clips with a transversely lying locking pin and free-standing locking pin, as well as all other types of counterpieces to the door lock on the opposing body component.
An inlet channel for the key collar is made in the housing of the motor vehicle door lock, often also in an additional mounting part which is located in the housing and which is generally called a catch bearing. The inlet channel is completed by the corresponding inlet slots in metal reinforcing plates on the front and/or back of the outside housing; they are often also called the first and the second rear sheet.
Rotary latches and detent pawls are typical lock elements of one such motor vehicle door lock, the rotary latch currently being made mostly as a fork latch with a preliminary catch and a main catch. The rotary latch and the detent pawl include ordinary additional parts such as the detent pawl spring and the rotary latch springs, as are of course known from the prior art. Motor vehicle door locks are also known with simply one locking catch, which replaces the rotary latch and the detent pawl, and these motor vehicle door locks also lie within the framework of this invention.
The blocking elements, bearing bolts for the blocking elements and the rear sheets generally consist of metal in order to be able to accommodate and deflect the tearing forces which occur in practice, especially in an accident. The outside housing, other mounting components and the catch bearing of a motor vehicle door lock currently consist mostly of plastic, often fiber-reinforced plastic. To some extent also metal inserts and metal parts are additionally used.
An electric lock is characterized by a minimum number of installation parts because the sole control function is lifting the detent pawl off the rotary latch. All other functions which are accomplished in mechanical door locks by lever arrangements are replaced in an electric lock by switching functions of the electronic circuit or the software by which the drive motor is triggered or not triggered.
The known electric lock disclosed in DE 195 45 722 A1 shows an outside housing which is essentially closed on all sides and which is made as a plastic molding. It is disclosed there that the outside housing according to one preferred development is made essentially symmetrical to its center plane which lies in or parallel to the plane of the rotary latch and detent pawl and consists of two half shells which are made of plastic, are provided on the outside with metallic reinforcing plates, and are connected to one another. This outside housing is made elongated and plate-like and on the two flat sides parallel to the center plane is provided in the half facing the lengthwise end with an inlet slot, the two inlet slots jointly forming the through inlet channel. The inlet channel with the inlet slots on the two flat sides of the outside housing is the catch bearing of the key collar.
The above explained construction of the known electric lock allows easy installation for both left-hand entry and right-hand entry of the key collar or also for middle entry of the key collar for example on a rear door or rear hatch. The flat and slender contour of the outside housing is also suited for limited installation space.
The above noted electric lock is disclosed on the one hand as a pure electric lock, in which redundancy is achieved by electrical means, for example by an extra battery or other additional power supply as disclosed in EP 0 589 158 A1, but can also be additionally equipped with auxiliary mechanical actuation of the detent pawl via Bowden cables. Reference should be made to these publications for the various possibilities of the configuration of auxiliary mechanical actuation.
In accordance with the present invention, there is no auxiliary mechanical actuation; it is intended to be primarily a pure electric lock with optionally electrically implemented redundancy. In any case auxiliary mechanical actuation accomplished as in the prior art is not entirely precluded, in particular does not contradict the implementation of the present invention.
In the above explained prior art, it has already been recognized that the concept of an electric lock offers a high level of antitheft protection, because even after forcible entry into the motor vehicle the door locks cannot be unlocked since the microswitches on the inside door handles have been deactivated via the control electronics. Due to the extensive encapsulation of the rotary latch and the detent pawl which is implemented in this motor vehicle door lock with the electric drive unit in the closed outside housing, it is not possible to act mechanically on the detent pawl either. It has, however, been recognized that the inlet slot theoretically offers a point of potential penetration. To this extent a special antitheft measure has been proposed such that in the outside housing there is an antitheft lever which blocks the detent pawl in the engaged position in a down position and which is pretensioned in the direction of the lifting position. This antitheft lever is activated by the electrical drive unit in the xe2x80x9cantitheftxe2x80x9d operating position of the electric lock.
In the above explained prior art, the electric drive unit has a drive motor, step-down gearing and a driven element. In this embodiment there is an electric drive motor which interacts via toothed gearing with a threaded spindle and a threaded rod in order to actuate the detent pawl. In another embodiment, the electric drive motor interacts with a worm gear pair with a worm gear as the driven element which has an eccentrically arranged arc-shaped crank of a certain contour which, upon actuation of the electric drive motor is caused to rotate and strikes the driver arm of the detent pawl lever which for its part lifts the detent pawl. The driver arm of the detent pawl lever is made so long that the crank can start in both directions of rotation. In one direction of rotation it acts with a low step-down ratio on the detent pawl so that the detent pawl is quickly lifted, in the opposite direction of rotation it acts with a much greater step-down ratio on the detent pawl lever and thus on the detent pawl so that an increased breakaway moment is available and opens the electric lock even with a high door counterpressure.
A corresponding drive unit of a motor vehicle door lock which operates likewise in two directions of rotation is disclosed in DE 197 10 531 A1, on the cam wheel which is used as the driven element there are two individual cams or journals which are offset by 180xc2x0 against one another in order to keep the starting times of the drive as short as possible.
Electric drive units are also known which work in only one direction of rotation, even if optionally reset by reversing under spring force, however, such devices have a degressive starting characteristic, therefore when starting they would first apply a high moment which as the lifting motion of the detent pawl continues is reduced incrementally or continuously as set forth in DE 41 19 703 C1.
In the above explained known electric lock, on the outside on the outside housing there is an electric terminal for the electrical terminals of the drive unit and the microswitches which are necessary for operation and which are located in the outside housing. For the microswitches which are designed to detect the position of the detent pawl and rotary latch and other operating states, electromechanical microswitches are typical, but at present so are also proximity switches, especially Hall switches. Reference is made to DE 195 45 722 A1. Contact can be made via a board or printed circuits which are cast into the plastic material of the outside housing. In this connection it is known that the drive motor of the electrical drive unit can be mechanically fixed and at the same time electrically connected by slipping it onto the terminal lugs of the circuit board.
Finally, the prior art discloses, particularly when using a worm gear pair as the step-down gearing with a cam wheel as the driven element, controlling the shutoff of the electric drive motor by a cam, journal or crank of the cam wheel striking a block via torque consumption, current consumption or a timer. Alternatively of course conventional switch controls with plug braking of the electric drive motor are known for these purposes.
The above explained motor vehicle door lock which provides a basis upon which the present invention evolves has a plastic outside housing which is essentially closed to the outside, with an interior largely protected against the entry of moisture. In this prior art; however, it has already been recognized that the inlet channel of the key collar remains as an entry area for moisture, therefore, this area must be sealed with measures known from the prior art, if this is considered necessary. Within the outside housing there is however the electrical drive unit with the corresponding circuit components so that in fact sealing of the inlet channel is necessary.
If the inlet channel for the key collar in practice cannot be optimally sealed, which will most often be the case, placing the electric drive unit in its own, separate sealed drive housing which is assembled with the outside housing can also be considered. This is known for a rear hatch lock as disclosed in DE 196 19 958 A1. In the electric lock disclosed therein the plastic, essentially closed drive housing contains an electric drive motor with step-down gearing and a cam wheel with two journal-shaped cams as the driven element. The drive housing is located side by side with the outside housing of the motor vehicle door lock, the outside housing containing only the rotary latch, the detent pawl and the detent pawl lever formed as an elongated arm of the detent pawl integrally therewith. The outside housing is not sealed. By way of an edge-side slot in the outside housing which is congruent with the corresponding slot in the drive housing, the detent pawl lever enters the drive housing from the outside housing and extends over to the cam wheel. On this end the detent pawl lever has a fork-shaped recess into which the respective cam of the cam wheel can fit.
The above described construction has sealing disadvantages due to the arrangement of the lengthwise slots.
Finally, a motor vehicle door lock, made with an outside housing which is not fully closed, but has a plurality of openings via which moisture can enter is known. This outside housing contains the rotary latch and the detent pawl as well as a plurality of levers of the lock mechanism. The outside housing bears the rotary latch and the detent pawl on one side of a center wall, held there by the rear sheet with the lever of the lock mechanism on the other side of the center wall. Ultimately the outside housing is reduced here to the peripheral edge of a plastic catch bearing.
A plastic housing cover in which the electrical conductors are injected is connected to the peripheral edge of the outside housing in the above noted motor vehicle door lock. The housing cover has a trough-shaped receiver open to the inside for the electrical drive unit which is sealed shut by a closing plate. On the inside the closing plate bears the electrical drive motor and the step-down gearing. The driven element of the step-down gearing is made as a cam wheel and is located on the opposing side, thus the outside of the closing plate. This cam wheel projects into the lock mechanism at suitable locations as soon as the housing cover has been joined to the edge of the outside housing. The cam wheel is sealed by the closing plate by way of a rotary bushing so that the receiver of the electrical drive unit is extremely well protected against moisture.
The above explained motor vehicle door lock is not an electric lock, but a mechanical motor vehicle door lock provided with an electrical central interlock system in which the electrical drive unit is best sealed against moisture by encapsulation of all components with an electrical function in a plastic housing cover.
Proceeding from the initially explained prior art detailed above, an object of the present invention is to optimize the known electric lock while maintaining the three-dimensionally optimum configuration of the outside housing both in the outside contour and in the interior.
Initially, the aforementioned object is achieved by way of an electric lock wherein the electric drive unit is located in an essentially closed drive housing which is sealed relative to the remainder of the outside housing and which itself is again located in the outside housing itself. For the electric drive unit therefore a housing in a housing is implemented, so that the drive housing itself in terms of sealing technology need simply manage the xe2x80x9cresidual moisturexe2x80x9d which has not already been kept out by the essentially closed outside housing. Viewed in this way, the drive housing implemented in accordance with the present invention itself is not in direct contact with the ambient atmosphere.
The sealing of the electrical drive unit is further optimized by the drive shaft of the cam wheel being sealed by way of a rotary bushing being routed through the wall of the drive housing and the cam wheel being located on the outside of the housing. Even in the implementation of the cam wheel as a driven element of the electric drive unit, in the past the exit from the closed drive housing had always been assigned to the translationally displaced detent pawl lever. In an electrical opening drive unit, as is implemented in an electric lock in accordance with the present invention, the implementation of a rotary bushing can ultimately be sealed much better than a bushing in which a level moves back and forth. This rotary bushing with its better sealing capacity advantageously optimizes the overall sealing of the electrical drive unit of the electric lock in accordance with the present invention.
According to a further object of the present invention, optimum blocking of the detent pawl lever which is in the closed position can be achieved. The antitheft feature of the detent pawl was heretofore explained in accordance with the aforementioned prior art devices. This required an additional antitheft lever moved by the electric drive motor. This lever blocks the detent pawl in the closed position only in the xe2x80x9cantitheftxe2x80x9d operating position, therefore with the vehicle stopped and locked from the outside.
In accordance with the present invention, the implementation of a pure electric lock with simply electrically implemented redundancy enables direct blocking of the detent pawl lever in the closed position by means of the driven element of the electric drive unit. With a drive unit designed to be self-locking, with the drive motor turned off the driven element cannot be pressed back mechanically on the part of the detent pawl lever. But it can be left blocking in front of the detent pawl lever. Since there is no emergency opening by hand, the detent pawl lever can be blocked in this way, thereby greatly simplifying this operation. This in turn leads to the fact that there need be no additional elements within the outside housing, the external shape of the outside housing and its internal configuration can remain essentially unchanged.
Accordingly, blocking of the detent pawl lever and thus of the detent pawl is achieved in a side impact. Complex measures are carried out for blocking of the detent pawl against unintentional lifting caused by acceleration forces, as implemented in DE 196 24 640 C1; GB 1 413 887 B; DE 41 17 110 C; DE 1 678 024 C. The same effect is achieved in the motor vehicle door lock of the present invention entirely without these complex measures, because the detent pawl is always blocked by the driven element even in the closed position and thus even with a side impact. The safety engineering aspect of emergency opening is satisfied in the electric lock in accordance with the present invention optionally via electrical redundancy.
The motor vehicle door lock set forth in accordance with the present invention can be especially feasibly installed based on its fundamental structural concept; it is possible to install the entire electric lock from only one direction, so that rotation of the workpiece during installation, as is necessary in all existing constructions, can be omitted. This special installation procedure and the particular construction of the motor vehicle door lock in accordance with the present invention in this respect are the subject matter of a parallel application filed substantially at the same time as the present application having U.S. application Ser. No. 10/032,695.
The invention is detailed below using drawings which show only one embodiment.